What To Do If Boiler Pressure Is Low

16th June 2022

Why is boiler pressure important?

Whether you have a combi boiler or a conventional boiler, it’s a complex system that requires your pipes and water system to work flawlessly. Every boiler heats cold water and circulates it around your property. Your pipes, radiators and hot water tank (if you have an older boiler) can only function if the boiler can heat water. The biggest issue with this is maintaining the correct pressure levels.

If a boiler’s pressure is too low, it won’t adequately heat cold water, which means households will be without both water and central heating. An inefficient boiler is bad news for your wallet, as it will use more energy than it needs.

What causes low boiler pressure?

The two most common causes of low boiler pressure are bleeding radiators and leaks. When you bleed a radiator, you release trapped air from the radiator, which often results in lower water pressure if too much escapes.

Even the tiniest of leaks can also cause problems with your boiler pressure, so it’s always a good idea to check around the boiler exterior to see if there are any wet patches. If there is a leak inside your boiler system, you should wait for a gas safe registered engineer to fix the problem – especially if there’s water damage to the electrics that control the boiler.

The good news is that most modern boilers have sensors built in to detect if the boiler has low pressure, or if it’s about to run low. If triggered, this will automatically place the boiler into a fault mode to protect the appliance and turn itself off. However, you’ll be left with no hot water – and a very cold home.

16th June 2022

How to increase your boiler pressure in 6 steps:

1. Turn off the boiler and make sure your central heating system is off, so you get a more accurate reading.
2. Locate the filling loop and the pressure gauge dial. A filling loop is a flexible, silver pipe with a valve. Most filling loops look like washing machine valves but it will have a black handle (or lever), which is situated horizontally across the pipe. This will turn 90 degrees in line with the pipe when moved.
3. Turn the black levers 90 degrees at each end of the filling loop (the silver braided hose with two black handles at each end). You should then hear water flowing.
4. Watch the pressure gauge carefully, as the dial can increase quite quickly as the water flows. If you cannot see the gauge make sure you get help so that you don’t over pressurise by mistake. The correct pressure is somewhere between 1 and 2 bars.
5. As soon as you have reached the right pressure, turn the handles on the filling loop by 90 degrees, in the opposite direction you turned them previously. Some filling loops might only have one lever, but that’s quite common. 
6. Your last step is to turn the boiler back on and reset it, if necessary, making sure that the gauge stays steady and doesn’t fluctuate up or down – once steady, you’re all set!

If you need assistance from a qualified Gas Safe engineer, get in touch with us here at Hometree.